Gold Member

Rouge is right to ask; people vary so much that it would really help to have some background. You titled the thread "needing ideas" -- if it was just "how do you initiate sex" that would make it clear it's just a call for stories.

With my now-serious girlfriend, she really gets turned on when she feels like she has a challenge. I either literally fight with her (rape fantasy/rape fantasy adjacent type of thing) until she's pinned down, then push her in to the wall and pound her hard. Tying her up is fun here too. We have a safe word and everything of course.
The other, easier way to initiate is to specifically not initiate. If I just ignore her even trying to kiss me on the cheek, it drives her crazy and before I know it she'll be grabbing my dick and forcing it inside her.